This invention relates to devices for collating and feeding screws, nails and other work articles of the same or similar configuration. Such feeders are utilized for supplying such articles to work stations where the articles may be further collated, transported or packaged or they may be used to carry out various operations such as fasten workpieces together, e.g. fastening hinges to door jambs.
Conventional screw feeders include devices such as those described in U.S. Pat. Nos. 2,943,764 and 4,222,495 which collate screws lying randomly in a receptacle by intercepting the screws with a collating device having one or more channels or slots into which the screws drop and which thus capture the screws in queued fashion. The screws are slidable within the slots so that when the slots are tilted above the horizontal about a pivot point at one end thereof, the queued screws will slide in the downhill direction. In this manner the screws are carried in each slot to the end of the slot at the pivot point. At the pivot point are entrances to a second set of slots which communicate with the respective first slots. The screws moving downward along the first slots will thus be transferred one-by-one, in a queue, into the second slots. The second slots are fixed and extend downwardly from their entrances so that the queue of screws will slide down the second slots to an escapement mechanism which will stop the queue and then separate each screw from the queue, consecutively depositing each screw into a receiver which transports each screw individually to an appropriate work station.
Screw feeders as described suffer from certain disadvantages due to the articulation required between the collating device and the receiving slots for the queued screws. An individual screw in the queue moving to the pivot point can become skewed. The skewed screw in the queue may not transfer properly to the receiving slot and instead become wedged at the junction between the slots, causing a plug of the slots. This requires a stoppage of the operation and manual clearing of the slot.
Additionally, in order to maintain the first set of slots in proper communication with the second set, particularly where the screw feeder is to be located in an industrial environment in which it will be subjected to rough treatment, possibly being hit by heavy objects, etc., strong and rigid construction is required, particularly at the pivot. This adds to the cost of construction and to supporting and operating the device due to its heaviness.